Multi-sensory experiences

03 Jun 2013 10min read

A hot topic in medical device development at the moment is improving the holistic user experience, but what does this actually mean?

There are so many different types of experiences that people can encounter with the same device and every time someone interacts with a product they will ‘experience’ something, whether the user experience is specifically designed or not.

There are many aspects that influence an individual’s experience of a product, some of these you can control and some you can’t. First and foremost you need to make sure that you deliver the right product (the right features, right shape and right size), to perform the required functions and meet the practical and lifestyle needs of the target users. To do this you need to consider the following five Ps: the Purpose, People, Place, Product and Process.

The five Ps can be used to explore and build a comprehensive set of use scenarios (including most likely, worst case and potentially stressful scenarios) to inform, guide and challenge development activities accordingly and ensure that the right product is developed. Now that we’re confident that we’re developing the right product, we should not ignore the importance of building an emotional connection with the user, which is particularly relevant in our industry, where people would quite simply prefer not to have to use a medical device. But how do we deliver a positive user experience?

How do we deliver a positive user experience?

We perceive our world through our five senses (sight, hearing, touch, smell and taste). When using products, we make a series of conscious and subconscious judgements based on our sensory interpretation and response. For example, some visual cues can subconsciously communicate intended interactions, whilst some audio clicks are consciously used to provide feedback for correct use. It is important to understand all potential responses and interpretations for all the relevant senses throughout a product’s life, to ensure that the right messages are communicated to the user at the right time. Mapping this holistic sensory journey not only leads to a more engaging experience from an emotional perspective but can also deliver more effective product outcomes in terms of user performance and compliance. Sensory mapping is crucial for users with some degree of sensory impairment, where there is a stronger reliance on the other senses. It is therefore important to understand the impact of certain conditions on sensory ability and design the sensory journey accordingly to provide appropriate feedback and prevent incorrect use.


Medical device manufacturers are becoming increasingly aware of the importance of a product’s visual language as appropriate visual cues not only lead to more aesthetically appealing products, but can also improve a product’s usability. There are many visual components to be considered as part of the visual design language, including product form, semiotics / semantics, aesthetic style, colour and material finish.

Depending on the market saturation of other products, it can sometimes be more detrimental to user safety to fundamentally redesign an unintuitive user interface, than to progressively improve key elements.

At different stages of the product life cycle, different types of visual cues become more important. For example, a user often forms an opinion about a product within the first few seconds of seeing it, and this first impression can often dominate their overall product opinion and experience. This first impression is usually based on their visual perception and so it is important that the appropriate messages are communicated from the outset.

It is also important that the visual language remains consistent throughout the product lifecycle and across all elements, including brand values, packaging, instructions, customer support and any other potential user touch points. The messages communicated should be complementary to avoid a confusing experience.

Individual users naturally develop their own mental models for product use based on previous product associations and experience. It is therefore important to explore similar devices and understand the associations that users may have with different colours, shapes, symbols, features and layouts. Depending on the market saturation of other products, it can sometimes be more detrimental to user safety to fundamentally redesign an unintuitive user interface, than to progressively improve key elements.

Another important aspect, often overlooked when entering new markets, is to explore and understand the different cultural associations that exist.


As the user starts to interact with a product, ‘touch’ and ‘feel’ become the more dominant senses. ‘Feel’ encompasses the physical form and materials used (often associated with touch), and also the motions, forces and other tactile characteristics which can significantly impact on ergonomics and usability.

As well as device ergonomics (the overall shape or form of a product), it is crucial to consider all other physical touch points such as buttons, levers, handles, moving parts, keypads, grips, or touch screens.

Product users with a visual impairment will rely on feel, associated sounds and – where applicable – smell to provide essential guidance and feedback regarding correct use. Therefore, all the physical touch points should be mapped and explored to ensure that any interaction is consistent with user expectations and other perceptual themes.

Just as certain visual properties can communicate different messages (such as ‘premium professional’ quality or ‘approachable’), the feel of the materials used and the tactile feedback from any moving parts can further support these themes. It is often difficult for users to articulate these particular preferences or associations, but different subliminal messages and characteristics can be communicated through the touch and feel of forms, motions and surfaces.

As well as device ergonomics (the overall shape or form of a product), it is crucial to consider all other physical touch points such as buttons, levers, handles, moving parts, keypads, grips, or touch screens. Surface quality (different textures, geometrical features or surface forms) can provide valuable guidance for use in terms of where and how to hold the device, as can the character of actions and moving parts. These can also convey different quality messages depending on the level of resistance, speed, consistency, and the specific path of the motion, and can also provide feedback which may influence user behaviour. An unintentional change in the character of a motion could therefore lead to incorrect use; for example, if a user plunging a syringe suddenly feels a resistive force, they may assume that the injection is complete, when in fact the force may be the trigger of a safety feature.


Sound can provide a range of feedbacks: that the device is working; that an action has been successfully completed; a warning that the user has done something wrong; or an alert or reminder. Sound can have a powerful influence on our holistic perception of a particular experience.

The subtleties of characterising a sound can be very complex and very different messages and tones can result from the loudness, timbre (tonal quality), frequency (pitch) and duration of the sound used.

The characteristics of the sound used should therefore reflect the messages to be communicated, and other perceptual product themes. For example, if a product communicates very soft, gentle and approachable messages through its visual language and tactile qualities, sharp, high-pitched sounds, harsh to the ear and annoying, are inappropriate for general feedback cues. However, a warning or alert should be distinctly different in its nature and tone, and difficult to ignore compared to sounds used for general feedback.

Hearing is one of those senses that is often subconsciously used

Some sounds can also fade into background noise after a prolonged period, such as the continuous drone of an aeroplane. Therefore it is important that high priority messages relating to safety are quickly recognised and cannot be ignored.

Hearing is one of those senses that is often subconsciously used but can have a powerful influence over our holistic perception of a particular experience.

For example, some car manufacturers spend a large amount of money and effort researching and engineering the car door catch to ensure the sound it makes when closing the door communicates the appropriate perception of quality. Although it may appear a minor factor in the bigger picture of car design and engineering, it is often the combination of all these relatively minor aspects which build the holistic experience and leave a lasting impression with the user.

It is also important to consider the unintentional sounds produced by other functions as these clicks, squeaks and rattles can often be misleading and can lead to user error. For example, when using an auto-injector, if a click is produced midway through drug delivery because another technical function is activated, this may be misinterpreted as a feedback cue for the end of the process, and as a result the user will not deliver the full dose.

Sounds can also draw unwanted attention. Most asthmatics, for example, want their inhaler use to be discrete, and so it is important to minimise and control any sounds given off during inhalation as these could reduce user motivation.


There are many examples where smell provides useful guidance for product use. For example, the preservative m-cresol in insulin has a very distinct anti-septic smell; visually impaired diabetics use this strong scent to indicate that the insulin has passed through the needle tip and the device is ‘ready’ to inject.

Research shows that smell has strong emotional connections; scent messages are carried to higher brain areas involved in conscious discrimination and perception of odours, and can trigger more primitive areas linked with emotions such as fear, loathing, love, and happiness. Smell also has very powerful connections with memory, which can have a significant influence on product experience (if used incorrectly), although it is often difficult to define and recreate particular odours, and emotional associations are often linked to personal experiences.

Some asthma patients use taste to indicate successful inhalation of their drug medication. Lactose, often used as a drug carrier in DPI formulations, is deposited at the back of the throat during inhalation leaving a sweet taste in the user’s mouth, and is often used as an indicator that the drug has been received.

If medication or drugs are to be taken through the mouth or nose, then the impact of smell and taste of the drug on the overall user experience cannot be ignored.

Other drugs that have a distinct smell can also affect the user experience and perception, especially those with a smell or taste that provokes emotional barriers to use by triggering negative memories associated with a particular smell or flavour.

Careful consideration of a user’s sensory journey can ensure the intended messages are delivered and can prompt the right product outcomes, leading to a more emotionally engaging user experience helping improve user motivation and hence increasing user compliance. Therefore, these relatively minor, apparently ‘low risk’ product characteristics are more important than many development teams realise, and can have a significant impact on ultimate product compliance.

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